/*
 * jcmaster.c
 *
 * Copyright (C) 1991-1995, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains master control logic for the JPEG compressor.
 * These routines are concerned with parameter validation, initial setup,
 * and inter-pass control (determining the number of passes and the work 
 * to be done in each pass).
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"


/* Private state */

typedef enum
{
	main_pass,					/* input data, also do first output step */
	huff_opt_pass,				/* Huffman code optimization pass */
	output_pass					/* data output pass */
} c_pass_type;

typedef struct
{
	struct jpeg_comp_master pub;	/* public fields */

	c_pass_type     pass_type;	/* the type of the current pass */

	int             pass_number;	/* # of passes completed */
	int             total_passes;	/* total # of passes needed */

	int             scan_number;	/* current index in scan_info[] */
} my_comp_master;

typedef my_comp_master *my_master_ptr;


/*
 * Support routines that do various essential calculations.
 */

LOCAL void initial_setup(j_compress_ptr cinfo)
/* Do computations that are needed before master selection phase */
{
	int             ci;
	jpeg_component_info *compptr;
	long            samplesperrow;
	JDIMENSION      jd_samplesperrow;

	/* Sanity check on image dimensions */
	if(cinfo->image_height <= 0 || cinfo->image_width <= 0 || cinfo->num_components <= 0 || cinfo->input_components <= 0)
		ERREXIT(cinfo, JERR_EMPTY_IMAGE);

	/* Make sure image isn't bigger than I can handle */
	if((long)cinfo->image_height > (long)JPEG_MAX_DIMENSION || (long)cinfo->image_width > (long)JPEG_MAX_DIMENSION)
		ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int)JPEG_MAX_DIMENSION);

	/* Width of an input scanline must be representable as JDIMENSION. */
	samplesperrow = (long)cinfo->image_width * (long)cinfo->input_components;
	jd_samplesperrow = (JDIMENSION) samplesperrow;
	if((long)jd_samplesperrow != samplesperrow)
		ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);

	/* For now, precision must match compiled-in value... */
	if(cinfo->data_precision != BITS_IN_JSAMPLE)
		ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);

	/* Check that number of components won't exceed internal array sizes */
	if(cinfo->num_components > MAX_COMPONENTS)
		ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, MAX_COMPONENTS);

	/* Compute maximum sampling factors; check factor validity */
	cinfo->max_h_samp_factor = 1;
	cinfo->max_v_samp_factor = 1;
	for(ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; ci++, compptr++)
	{
		if(compptr->h_samp_factor <= 0 || compptr->h_samp_factor > MAX_SAMP_FACTOR ||
		   compptr->v_samp_factor <= 0 || compptr->v_samp_factor > MAX_SAMP_FACTOR)
			ERREXIT(cinfo, JERR_BAD_SAMPLING);
		cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor, compptr->h_samp_factor);
		cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor, compptr->v_samp_factor);
	}

	/* Compute dimensions of components */
	for(ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; ci++, compptr++)
	{
		/* Fill in the correct component_index value; don't rely on application */
		compptr->component_index = ci;
		/* For compression, we never do DCT scaling. */
		compptr->DCT_scaled_size = DCTSIZE;
		/* Size in DCT blocks */
		compptr->width_in_blocks = (JDIMENSION)
			jdiv_round_up((long)cinfo->image_width * (long)compptr->h_samp_factor, (long)(cinfo->max_h_samp_factor * DCTSIZE));
		compptr->height_in_blocks = (JDIMENSION)
			jdiv_round_up((long)cinfo->image_height * (long)compptr->v_samp_factor, (long)(cinfo->max_v_samp_factor * DCTSIZE));
		/* Size in samples */
		compptr->downsampled_width = (JDIMENSION)
			jdiv_round_up((long)cinfo->image_width * (long)compptr->h_samp_factor, (long)cinfo->max_h_samp_factor);
		compptr->downsampled_height = (JDIMENSION)
			jdiv_round_up((long)cinfo->image_height * (long)compptr->v_samp_factor, (long)cinfo->max_v_samp_factor);
		/* Mark component needed (this flag isn't actually used for compression) */
		compptr->component_needed = TRUE;
	}

	/* Compute number of fully interleaved MCU rows (number of times that
	 * main controller will call coefficient controller).
	 */
	cinfo->total_iMCU_rows = (JDIMENSION) jdiv_round_up((long)cinfo->image_height, (long)(cinfo->max_v_samp_factor * DCTSIZE));
}


#ifdef C_MULTISCAN_FILES_SUPPORTED

LOCAL void validate_script(j_compress_ptr cinfo)
/* Verify that the scan script in cinfo->scan_info[] is valid; also
 * determine whether it uses progressive JPEG, and set cinfo->progressive_mode.
 */
{
	const jpeg_scan_info *scanptr;
	int             scanno, ncomps, ci, coefi, thisi;
	int             Ss, Se, Ah, Al;
	boolean         component_sent[MAX_COMPONENTS];

#ifdef C_PROGRESSIVE_SUPPORTED
	int            *last_bitpos_ptr;
	int             last_bitpos[MAX_COMPONENTS][DCTSIZE2];

	/* -1 until that coefficient has been seen; then last Al for it */
#endif

	if(cinfo->num_scans <= 0)
		ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0);

	/* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1;
	 * for progressive JPEG, no scan can have this.
	 */
	scanptr = cinfo->scan_info;
	if(scanptr->Ss != 0 || scanptr->Se != DCTSIZE2 - 1)
	{
#ifdef C_PROGRESSIVE_SUPPORTED
		cinfo->progressive_mode = TRUE;
		last_bitpos_ptr = &last_bitpos[0][0];
		for(ci = 0; ci < cinfo->num_components; ci++)
			for(coefi = 0; coefi < DCTSIZE2; coefi++)
				*last_bitpos_ptr++ = -1;
#else
		ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
	}
	else
	{
		cinfo->progressive_mode = FALSE;
		for(ci = 0; ci < cinfo->num_components; ci++)
			component_sent[ci] = FALSE;
	}

	for(scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++)
	{
		/* Validate component indexes */
		ncomps = scanptr->comps_in_scan;
		if(ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN)
			ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN);
		for(ci = 0; ci < ncomps; ci++)
		{
			thisi = scanptr->component_index[ci];
			if(thisi < 0 || thisi >= cinfo->num_components)
				ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
			/* Components must appear in SOF order within each scan */
			if(ci > 0 && thisi <= scanptr->component_index[ci - 1])
				ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
		}
		/* Validate progression parameters */
		Ss = scanptr->Ss;
		Se = scanptr->Se;
		Ah = scanptr->Ah;
		Al = scanptr->Al;
		if(cinfo->progressive_mode)
		{
#ifdef C_PROGRESSIVE_SUPPORTED
			if(Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 || Ah < 0 || Ah > 13 || Al < 0 || Al > 13)
				ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
			if(Ss == 0)
			{
				if(Se != 0)		/* DC and AC together not OK */
					ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
			}
			else
			{
				if(ncomps != 1)	/* AC scans must be for only one component */
					ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
			}
			for(ci = 0; ci < ncomps; ci++)
			{
				last_bitpos_ptr = &last_bitpos[scanptr->component_index[ci]][0];
				if(Ss != 0 && last_bitpos_ptr[0] < 0)	/* AC without prior DC scan */
					ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
				for(coefi = Ss; coefi <= Se; coefi++)
				{
					if(last_bitpos_ptr[coefi] < 0)
					{
						/* first scan of this coefficient */
						if(Ah != 0)
							ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
					}
					else
					{
						/* not first scan */
						if(Ah != last_bitpos_ptr[coefi] || Al != Ah - 1)
							ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
					}
					last_bitpos_ptr[coefi] = Al;
				}
			}
#endif
		}
		else
		{
			/* For sequential JPEG, all progression parameters must be these: */
			if(Ss != 0 || Se != DCTSIZE2 - 1 || Ah != 0 || Al != 0)
				ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno);
			/* Make sure components are not sent twice */
			for(ci = 0; ci < ncomps; ci++)
			{
				thisi = scanptr->component_index[ci];
				if(component_sent[thisi])
					ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno);
				component_sent[thisi] = TRUE;
			}
		}
	}

	/* Now verify that everything got sent. */
	if(cinfo->progressive_mode)
	{
#ifdef C_PROGRESSIVE_SUPPORTED
		/* For progressive mode, we only check that at least some DC data
		 * got sent for each component; the spec does not require that all bits
		 * of all coefficients be transmitted.  Would it be wiser to enforce
		 * transmission of all coefficient bits??
		 */
		for(ci = 0; ci < cinfo->num_components; ci++)
		{
			if(last_bitpos[ci][0] < 0)
				ERREXIT(cinfo, JERR_MISSING_DATA);
		}
#endif
	}
	else
	{
		for(ci = 0; ci < cinfo->num_components; ci++)
		{
			if(!component_sent[ci])
				ERREXIT(cinfo, JERR_MISSING_DATA);
		}
	}
}

#endif							/* C_MULTISCAN_FILES_SUPPORTED */


LOCAL void select_scan_parameters(j_compress_ptr cinfo)
/* Set up the scan parameters for the current scan */
{
	int             ci;

#ifdef C_MULTISCAN_FILES_SUPPORTED
	if(cinfo->scan_info != NULL)
	{
		/* Prepare for current scan --- the script is already validated */
		my_master_ptr   master = (my_master_ptr) cinfo->master;
		const jpeg_scan_info *scanptr = cinfo->scan_info + master->scan_number;

		cinfo->comps_in_scan = scanptr->comps_in_scan;
		for(ci = 0; ci < scanptr->comps_in_scan; ci++)
		{
			cinfo->cur_comp_info[ci] = &cinfo->comp_info[scanptr->component_index[ci]];
		}
		cinfo->Ss = scanptr->Ss;
		cinfo->Se = scanptr->Se;
		cinfo->Ah = scanptr->Ah;
		cinfo->Al = scanptr->Al;
	}
	else
#endif
	{
		/* Prepare for single sequential-JPEG scan containing all components */
		if(cinfo->num_components > MAX_COMPS_IN_SCAN)
			ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, MAX_COMPS_IN_SCAN);
		cinfo->comps_in_scan = cinfo->num_components;
		for(ci = 0; ci < cinfo->num_components; ci++)
		{
			cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci];
		}
		cinfo->Ss = 0;
		cinfo->Se = DCTSIZE2 - 1;
		cinfo->Ah = 0;
		cinfo->Al = 0;
	}
}


LOCAL void per_scan_setup(j_compress_ptr cinfo)
/* Do computations that are needed before processing a JPEG scan */
/* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */
{
	int             ci, mcublks, tmp;
	jpeg_component_info *compptr;

	if(cinfo->comps_in_scan == 1)
	{

		/* Noninterleaved (single-component) scan */
		compptr = cinfo->cur_comp_info[0];

		/* Overall image size in MCUs */
		cinfo->MCUs_per_row = compptr->width_in_blocks;
		cinfo->MCU_rows_in_scan = compptr->height_in_blocks;

		/* For noninterleaved scan, always one block per MCU */
		compptr->MCU_width = 1;
		compptr->MCU_height = 1;
		compptr->MCU_blocks = 1;
		compptr->MCU_sample_width = DCTSIZE;
		compptr->last_col_width = 1;
		/* For noninterleaved scans, it is convenient to define last_row_height
		 * as the number of block rows present in the last iMCU row.
		 */
		tmp = (int)(compptr->height_in_blocks % compptr->v_samp_factor);
		if(tmp == 0)
			tmp = compptr->v_samp_factor;
		compptr->last_row_height = tmp;

		/* Prepare array describing MCU composition */
		cinfo->blocks_in_MCU = 1;
		cinfo->MCU_membership[0] = 0;

	}
	else
	{

		/* Interleaved (multi-component) scan */
		if(cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
			ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan, MAX_COMPS_IN_SCAN);

		/* Overall image size in MCUs */
		cinfo->MCUs_per_row = (JDIMENSION) jdiv_round_up((long)cinfo->image_width, (long)(cinfo->max_h_samp_factor * DCTSIZE));
		cinfo->MCU_rows_in_scan = (JDIMENSION)
			jdiv_round_up((long)cinfo->image_height, (long)(cinfo->max_v_samp_factor * DCTSIZE));

		cinfo->blocks_in_MCU = 0;

		for(ci = 0; ci < cinfo->comps_in_scan; ci++)
		{
			compptr = cinfo->cur_comp_info[ci];
			/* Sampling factors give # of blocks of component in each MCU */
			compptr->MCU_width = compptr->h_samp_factor;
			compptr->MCU_height = compptr->v_samp_factor;
			compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
			compptr->MCU_sample_width = compptr->MCU_width * DCTSIZE;
			/* Figure number of non-dummy blocks in last MCU column & row */
			tmp = (int)(compptr->width_in_blocks % compptr->MCU_width);
			if(tmp == 0)
				tmp = compptr->MCU_width;
			compptr->last_col_width = tmp;
			tmp = (int)(compptr->height_in_blocks % compptr->MCU_height);
			if(tmp == 0)
				tmp = compptr->MCU_height;
			compptr->last_row_height = tmp;
			/* Prepare array describing MCU composition */
			mcublks = compptr->MCU_blocks;
			if(cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU)
				ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
			while(mcublks-- > 0)
			{
				cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
			}
		}

	}

	/* Convert restart specified in rows to actual MCU count. */
	/* Note that count must fit in 16 bits, so we provide limiting. */
	if(cinfo->restart_in_rows > 0)
	{
		long            nominal = (long)cinfo->restart_in_rows * (long)cinfo->MCUs_per_row;

		cinfo->restart_interval = (unsigned int)MIN(nominal, 65535L);
	}
}


/*
 * Per-pass setup.
 * This is called at the beginning of each pass.  We determine which modules
 * will be active during this pass and give them appropriate start_pass calls.
 * We also set is_last_pass to indicate whether any more passes will be
 * required.
 */

METHODDEF void prepare_for_pass(j_compress_ptr cinfo)
{
	my_master_ptr   master = (my_master_ptr) cinfo->master;

	switch (master->pass_type)
	{
		case main_pass:
			/* Initial pass: will collect input data, and do either Huffman
			 * optimization or data output for the first scan.
			 */
			select_scan_parameters(cinfo);
			per_scan_setup(cinfo);
			if(!cinfo->raw_data_in)
			{
				(*cinfo->cconvert->start_pass) (cinfo);
				(*cinfo->downsample->start_pass) (cinfo);
				(*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU);
			}
			(*cinfo->fdct->start_pass) (cinfo);
			(*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding);
			(*cinfo->coef->start_pass) (cinfo, (master->total_passes > 1 ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU));
			(*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU);
			if(cinfo->optimize_coding)
			{
				/* No immediate data output; postpone writing frame/scan headers */
				master->pub.call_pass_startup = FALSE;
			}
			else
			{
				/* Will write frame/scan headers at first jpeg_write_scanlines call */
				master->pub.call_pass_startup = TRUE;
			}
			break;
#ifdef ENTROPY_OPT_SUPPORTED
		case huff_opt_pass:
			/* Do Huffman optimization for a scan after the first one. */
			select_scan_parameters(cinfo);
			per_scan_setup(cinfo);
			if(cinfo->Ss != 0 || cinfo->Ah == 0 || cinfo->arith_code)
			{
				(*cinfo->entropy->start_pass) (cinfo, TRUE);
				(*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
				master->pub.call_pass_startup = FALSE;
				break;
			}
			/* Special case: Huffman DC refinement scans need no Huffman table
			 * and therefore we can skip the optimization pass for them.
			 */
			master->pass_type = output_pass;
			master->pass_number++;
			 /*FALLTHROUGH*/
#endif
		case output_pass:
			/* Do a data-output pass. */
			/* We need not repeat per-scan setup if prior optimization pass did it. */
			if(!cinfo->optimize_coding)
			{
				select_scan_parameters(cinfo);
				per_scan_setup(cinfo);
			}
			(*cinfo->entropy->start_pass) (cinfo, FALSE);
			(*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST);
			/* We emit frame/scan headers now */
			if(master->scan_number == 0)
				(*cinfo->marker->write_frame_header) (cinfo);
			(*cinfo->marker->write_scan_header) (cinfo);
			master->pub.call_pass_startup = FALSE;
			break;
		default:
			ERREXIT(cinfo, JERR_NOT_COMPILED);
	}

	master->pub.is_last_pass = (master->pass_number == master->total_passes - 1);

	/* Set up progress monitor's pass info if present */
	if(cinfo->progress != NULL)
	{
		cinfo->progress->completed_passes = master->pass_number;
		cinfo->progress->total_passes = master->total_passes;
	}
}


/*
 * Special start-of-pass hook.
 * This is called by jpeg_write_scanlines if call_pass_startup is TRUE.
 * In single-pass processing, we need this hook because we don't want to
 * write frame/scan headers during jpeg_start_compress; we want to let the
 * application write COM markers etc. between jpeg_start_compress and the
 * jpeg_write_scanlines loop.
 * In multi-pass processing, this routine is not used.
 */

METHODDEF void pass_startup(j_compress_ptr cinfo)
{
	cinfo->master->call_pass_startup = FALSE;	/* reset flag so call only once */

	(*cinfo->marker->write_frame_header) (cinfo);
	(*cinfo->marker->write_scan_header) (cinfo);
}


/*
 * Finish up at end of pass.
 */

METHODDEF void finish_pass_master(j_compress_ptr cinfo)
{
	my_master_ptr   master = (my_master_ptr) cinfo->master;

	/* The entropy coder always needs an end-of-pass call,
	 * either to analyze statistics or to flush its output buffer.
	 */
	(*cinfo->entropy->finish_pass) (cinfo);

	/* Update state for next pass */
	switch (master->pass_type)
	{
		case main_pass:
			/* next pass is either output of scan 0 (after optimization)
			 * or output of scan 1 (if no optimization).
			 */
			master->pass_type = output_pass;
			if(!cinfo->optimize_coding)
				master->scan_number++;
			break;
		case huff_opt_pass:
			/* next pass is always output of current scan */
			master->pass_type = output_pass;
			break;
		case output_pass:
			/* next pass is either optimization or output of next scan */
			if(cinfo->optimize_coding)
				master->pass_type = huff_opt_pass;
			master->scan_number++;
			break;
	}

	master->pass_number++;
}


/*
 * Initialize master compression control.
 */

GLOBAL void jinit_c_master_control(j_compress_ptr cinfo, boolean transcode_only)
{
	my_master_ptr   master;

	master = (my_master_ptr) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, SIZEOF(my_comp_master));
	cinfo->master = (struct jpeg_comp_master *)master;
	master->pub.prepare_for_pass = prepare_for_pass;
	master->pub.pass_startup = pass_startup;
	master->pub.finish_pass = finish_pass_master;
	master->pub.is_last_pass = FALSE;

	/* Validate parameters, determine derived values */
	initial_setup(cinfo);

	if(cinfo->scan_info != NULL)
	{
#ifdef C_MULTISCAN_FILES_SUPPORTED
		validate_script(cinfo);
#else
		ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
	}
	else
	{
		cinfo->progressive_mode = FALSE;
		cinfo->num_scans = 1;
	}

	if(cinfo->progressive_mode)	/*  TEMPORARY HACK ??? */
		cinfo->optimize_coding = TRUE;	/* assume default tables no good for progressive mode */

	/* Initialize my private state */
	if(transcode_only)
	{
		/* no main pass in transcoding */
		if(cinfo->optimize_coding)
			master->pass_type = huff_opt_pass;
		else
			master->pass_type = output_pass;
	}
	else
	{
		/* for normal compression, first pass is always this type: */
		master->pass_type = main_pass;
	}
	master->scan_number = 0;
	master->pass_number = 0;
	if(cinfo->optimize_coding)
		master->total_passes = cinfo->num_scans * 2;
	else
		master->total_passes = cinfo->num_scans;
}
